Signal conversion apparatus and display apparatus using the same

Abstract

A signal conversion apparatus allows long distance transmission while suppressing cross talk between adjacent signal lines and the introduction of external noise, even when signals are transmitted at a high rate. The signal conversion apparatus is interposed between an image signal source for outputting in image signal and a display apparatus for displaying an image in accordance with the image signal and includes a first conversion unit for converting an unbalanced signal supplied from the image signal source to a balanced signal, and a second conversion unit for converting the balanced signal outputted by the first conversion unit and outputting it to the display apparatus.

What is claimed is: 
     
       1. A signal conversion apparatus to be interposed between an image signal source for outputting an image signal having a logical level and a display apparatus for displaying an image in accordance with the image signal, said apparatus comprising: a first conversion unit for converting an unbalanced signal having a logical level input from the image signal source to a balanced signal having a logical level and outputting the balanced signal; and   a second conversion unit for converting the balanced signal output by said first conversion unit to an unbalanced signal having a logical level and outputting the same to the display apparatus.   
     
     
       2. A signal conversion apparatus according to claim 1 wherein each of said first and second conversion units includes a non-conversion terminal for inputting and outputting a signal not to be converted, a conversion terminal for inputting and outputting a signal to be converted, signal conversion means for not effecting the conversion for the signal input and output through said non-conversion terminal and effecting the conversion between the unbalanced signal having the logical level and the balanced signal having the logical level for the signal input and output through said conversion terminal, and means for selecting directions of input and output of the signals input and output to said signal conversion means. 
     
     
       3. A signal conversion apparatus according to claim 2, wherein each of said first and second conversion units includes means for rendering the output thereof to a high resistance state. 
     
     
       4. A signal conversion apparatus according to claim 2, wherein said first and second conversion units are of identical configuration. 
     
     
       5. A signal conversion apparatus according to any of claims 1 to 4, wherein said display apparatus is a liquid crystal display apparatus. 
     
     
       6. A signal conversion apparatus according to any of claims 1 to 4, wherein said image signal source is one in number and said display apparatus and said second conversion unit are plural in number. 
     
     
       7. A signal conversion apparatus according to any of claims 1 to 4, wherein said display apparatus is a liquid crystal display apparatus having a ferroelectric property.